Channel oriented tone reservation for multiple input multiple output communications

ABSTRACT

Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a user equipment (UE) may transmit an indication that the UE supports multiple input multiple output (MIMO) tone reservation. The UE may receive a MIMO communication having tone reservation applied to tone reservation (TR) subcarriers of the MIMO communication. Numerous other aspects are described.

FIELD OF THE DISCLOSURE

Aspects of the present disclosure generally relate to wireless communication and to techniques and apparatuses for channel oriented tone reservation for multiple input multiple output communications.

BACKGROUND

Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, or the like). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency-division multiple access (FDMA) systems, orthogonal frequency-division multiple access (OFDMA) systems, single-carrier frequency-division multiple access (SC-FDMA) systems, time division synchronous code division multiple access (TD-SCDMA) systems, and Long Term Evolution (LTE). LTE/LTE-Advanced is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP).

A wireless network may include a number of base stations (BSs) that can support communication for a number of user equipment (UEs). A UE may communicate with a BS via the downlink and uplink. The downlink (or forward link) refers to the communication link from the BS to the UE, and the uplink (or reverse link) refers to the communication link from the UE to the BS. As will be described in more detail herein, a BS may be referred to as a Node B, a gNB, an access point (AP), a radio head, a transmit receive point (TRP), a New Radio (NR) BS, a 5G Node B, or the like.

The above multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different user equipment to communicate on a municipal, national, regional, and even global level. NR, which may also be referred to as 5G, is a set of enhancements to the LTE mobile standard promulgated by the 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using orthogonal frequency division multiplexing (OFDM) with a cyclic prefix (CP) (CP-OFDM) on the downlink (DL), using CP-OFDM and/or SC-FDM (e.g., also known as discrete Fourier transform spread OFDM (DFT-s-OFDM)) on the uplink (UL), as well as supporting beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. As the demand for mobile broadband access continues to increase, further improvements in LTE, NR, and other radio access technologies remain useful.

SUMMARY

In some aspects, a method of wireless communication performed by a user equipment (UE) includes transmitting an indication that the UE supports multiple input multiple output (MIMO) tone reservation; and receiving a MIMO communication having tone reservation applied to tone reservation (TR) subcarriers of the MIMO communication.

In some aspects, a method of wireless communication performed by a base station includes receiving an indication that a UE supports MIMO tone reservation; and transmitting a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a method of wireless communication performed by a UE includes transmitting an indication that the UE supports MIMO tone reservation; and transmitting a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a method of wireless communication performed by a base station includes receiving an indication that a UE supports MIMO tone reservation; and receiving a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a UE for wireless communication includes a memory; and one or more processors, coupled to the memory, configured to: transmit an indication that the UE supports MIMO tone reservation; and receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a base station for wireless communication includes a memory; and one or more processors, coupled to the memory, configured to: receive an indication that a UE supports MIMO tone reservation; and transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a UE for wireless communication includes a memory; and one or more processors, coupled to the memory, configured to: transmit an indication that the UE supports MIMO tone reservation; and transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a base station for wireless communication includes a memory; and one or more processors, coupled to the memory, configured to: receive an indication that a UE supports MIMO tone reservation; and receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a non-transitory computer-readable medium stores a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a UE, cause the UE to: transmit an indication that the UE supports MIMO tone reservation; and receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a non-transitory computer-readable medium stores a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a base station, cause the base station to: receive an indication that a UE supports MIMO tone reservation; and transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a non-transitory computer-readable medium stores a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a UE, cause the UE to: transmit an indication that the UE supports MIMO tone reservation; and transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, a non-transitory computer-readable medium stores a set of instructions for wireless communication includes one or more instructions that, when executed by one or more processors of a base station, cause the base station to: receive an indication that a UE supports MIMO tone reservation; and receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, an apparatus for wireless communication includes means for transmitting an indication that the apparatus supports MIMO tone reservation; and means for receiving a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, an apparatus for wireless communication includes means for receiving an indication that a UE supports MIMO tone reservation; and means for transmitting a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, an apparatus for wireless communication includes means for transmitting an indication that the apparatus supports MIMO tone reservation; and means for transmitting a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

In some aspects, an apparatus for wireless communication includes means for receiving an indication that a UE supports MIMO tone reservation; and means for receiving a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

Aspects generally include a method, apparatus, system, computer program product, non-transitory computer-readable medium, user equipment, base station, wireless communication device, and/or processing system as substantially described herein with reference to and as illustrated by the drawings and specification.

The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims.

While aspects are described in the present disclosure by illustration to some examples, those skilled in the art will understand that such aspects may be implemented in many different arrangements and scenarios. Techniques described herein may be implemented using different platform types, devices, systems, shapes, sizes, and/or packaging arrangements. For example, some aspects may be implemented via integrated chip embodiments or other non-module-component based devices (e.g., end-user devices, vehicles, communication devices, computing devices, industrial equipment, retail/purchasing devices, medical devices, or artificial intelligence-enabled devices). Aspects may be implemented in chip-level components, modular components, non-modular components, non-chip-level components, device-level components, or system-level components. Devices incorporating described aspects and features may include additional components and features for implementation and practice of claimed and described aspects. For example, transmission and reception of wireless signals may include a number of components for analog and digital purposes (e.g., hardware components including antenna, radio frequency (RF) chains, power amplifiers, modulators, buffer, processor(s), interleaver, adders, or summers). It is intended that aspects described herein may be practiced in a wide variety of devices, components, systems, distributed arrangements, or end-user devices of varying size, shape, and constitution.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. The same reference numbers in different drawings may identify the same or similar elements.

FIG. 1 is a diagram illustrating an example of a wireless network, in accordance with the present disclosure.

FIG. 2 is a diagram illustrating an example of a base station in communication with a user equipment (UE) in a wireless network, in accordance with the present disclosure.

FIG. 3 is a diagram illustrating an example of tone reservation, in accordance with the present disclosure.

FIGS. 4-6 are diagrams illustrating examples associated with channel oriented tone reservation for multiple input multiple output communications, in accordance with the present disclosure.

FIGS. 7-10 are diagrams illustrating example processes associated with channel oriented tone reservation for multiple input multiple output communications, in accordance with the present disclosure.

FIGS. 11 and 12 are block diagrams of example apparatuses for wireless communication, in accordance with the present disclosure.

DETAILED DESCRIPTION

Tone reservation (TR) (e.g., foregoing transmission of data on one or more subcarriers of a communication and/or transmitting a signal to improve a peak-to-average-power ratio (PAPR) of the communication on the one or more subcarriers, among other examples) may be used by a transmitting device to improve PAPR of a communication to a receiving device. This may improve a likelihood of decoding and/or demodulating the communication by the receiving device. Tone reservation may be applied to fixed subcarriers, which reduces throughput on the communication and may replace data on high-capacity subcarriers that have a relatively high likelihood of being decoded and demodulated by the receiving device. Alternatively, tone reservation may be applied to subcarriers that are based at least in part on capacities of the subcarriers as expected to be received by the receiving device (e.g., using low capacity subcarriers). However, signaling for use of tone reservation may consume resources as overhead, which may decrease throughput and/or spectral efficiency.

In some aspects described herein, a transmitting device (e.g., a base station or a user equipment (UE), among other examples) may transmit an indication that tone reservation is to be applied to one or more subcarriers for a MIMO communication having multiple streams, and a receiving device (e.g., a UE or a base station, among other examples) may receive the indication. The indication may provide parameters for estimating TR subcarriers having tone reservation applied for the communication based at least in part on optimizing a peak-to-average-power ratio across the multiple streams of the MIMO communication.

The transmitting device may select the TR subcarriers based at least in part on an estimate of a channel response at the receiving device (e.g., may select TR subcarriers as the lowest capacity subcarriers of the communication as observed at the receiving device). The receiving device may estimate the TR subcarriers (e.g., attempt to identify the TR subcarriers) based at least in part on capacities of subcarriers of the communication, with the capacities determined using demodulation reference signals (DMRSs) and/or data symbols of the communication. Based at least in part on determining the capacities of the subcarriers, the receiving device may identify the TR subcarriers and decode the communication based at least in part on zeroing out the TR subcarriers or discarding the TR subcarriers.

Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein, one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.

Several aspects of telecommunication systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, or the like (collectively referred to as “elements”). These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

It should be noted that while aspects may be described herein using terminology commonly associated with a 5G or NR radio access technology (RAT), aspects of the present disclosure can be applied to other RATs, such as a 3G RAT, a 4G RAT, and/or a RAT subsequent to 5G (e.g., 6G).

FIG. 1 is a diagram illustrating an example of a wireless network 100, in accordance with the present disclosure. The wireless network 100 may be or may include elements of a 5G (NR) network and/or an LTE network, among other examples. The wireless network 100 may include a number of base stations 110 (shown as BS 110 a, BS 110 b, BS 110 c, and BS 110 d) and other network entities. A base station (BS) is an entity that communicates with UEs and may also be referred to as an NR BS, a Node B, a gNB, a 5G node B (NB), an access point, a transmit receive point (TRP), or the like. Each BS may provide communication coverage for a particular geographic area. In 3GPP, the term “cell” can refer to a coverage area of a BS and/or a BS subsystem serving this coverage area, depending on the context in which the term is used.

A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or another type of cell. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having association with the femto cell (e.g., UEs in a closed subscriber group (CSG)). ABS for a macro cell may be referred to as a macro BS. ABS for a pico cell may be referred to as a pico BS. A BS for a femto cell may be referred to as a femto BS or a home BS. In the example shown in FIG. 1 , a BS 110 a may be a macro BS for a macro cell 102 a, a BS 110 b may be a pico BS for a pico cell 102 b, and a BS 110 c may be a femto BS for a femto cell 102 c. A BS may support one or multiple (e.g., three) cells. The terms “eNB”, “base station”, “NR BS”, “gNB”, “TRP”, “AP”, “node B”, “5G NB”, and “cell” may be used interchangeably herein.

In some aspects, a cell may not necessarily be stationary, and the geographic area of the cell may move according to the location of a mobile BS. In some aspects, the BSs may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in the wireless network 100 through various types of backhaul interfaces, such as a direct physical connection or a virtual network, using any suitable transport network.

Wireless network 100 may also include relay stations. A relay station is an entity that can receive a transmission of data from an upstream station (e.g., a BS or a UE) and send a transmission of the data to a downstream station (e.g., a UE or a BS). A relay station may also be a UE that can relay transmissions for other UEs. In the example shown in FIG. 1 , a relay BS 110 d may communicate with macro BS 110 a and a UE 120 d in order to facilitate communication between BS 110 a and UE 120 d. A relay BS may also be referred to as a relay station, a relay base station, a relay, or the like.

Wireless network 100 may be a heterogeneous network that includes BSs of different types, such as macro BSs, pico BSs, femto BSs, relay BSs, or the like. These different types of BSs may have different transmit power levels, different coverage areas, and different impacts on interference in wireless network 100. For example, macro BSs may have a high transmit power level (e.g., 5 to 40 watts) whereas pico BSs, femto BSs, and relay BSs may have lower transmit power levels (e.g., 0.1 to 2 watts).

A network controller 130 may couple to a set of BSs and may provide coordination and control for these BSs. Network controller 130 may communicate with the BSs via a backhaul. The BSs may also communicate with one another, e.g., directly or indirectly via a wireless or wireline backhaul.

UEs 120 (e.g., 120 a, 120 b, 120 c) may be dispersed throughout wireless network 100, and each UE may be stationary or mobile. A UE may also be referred to as an access terminal, a terminal, a mobile station, a subscriber unit, a station, or the like. A UE may be a cellular phone (e.g., a smart phone), a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet, a camera, a gaming device, a netbook, a smartbook, an ultrabook, a medical device or equipment, biometric sensors/devices, wearable devices (smart watches, smart clothing, smart glasses, smart wrist bands, smart jewelry (e.g., smart ring, smart bracelet)), an entertainment device (e.g., a music or video device, or a satellite radio), a vehicular component or sensor, smart meters/sensors, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium.

Some UEs may be considered machine-type communication (MTC) or evolved or enhanced machine-type communication (eMTC) UEs. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, and/or location tags, that may communicate with a base station, another device (e.g., remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, and/or may be implemented as NB-IoT (narrowband internet of things) devices. Some UEs may be considered a Customer Premises Equipment (CPE). UE 120 may be included inside a housing that houses components of UE 120, such as processor components and/or memory components. In some aspects, the processor components and the memory components may be coupled together. For example, the processor components (e.g., one or more processors) and the memory components (e.g., a memory) may be operatively coupled, communicatively coupled, electronically coupled, and/or electrically coupled.

In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular RAT and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, or the like. A frequency may also be referred to as a carrier, a frequency channel, or the like. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, NR or 5G RAT networks may be deployed.

In some aspects, two or more UEs 120 (e.g., shown as UE 120 a and UE 120 e) may communicate directly using one or more sidelink channels (e.g., without using a base station 110 as an intermediary to communicate with one another). For example, the UEs 120 may communicate using peer-to-peer (P2P) communications, device-to-device (D2D) communications, a vehicle-to-everything (V2X) protocol (e.g., which may include a vehicle-to-vehicle (V2V) protocol or a vehicle-to-infrastructure (V2I) protocol), and/or a mesh network. In this case, the UE 120 may perform scheduling operations, resource selection operations, and/or other operations described elsewhere herein as being performed by the base station 110.

Devices of wireless network 100 may communicate using the electromagnetic spectrum, which may be subdivided based on frequency or wavelength into various classes, bands, channels, or the like. For example, devices of wireless network 100 may communicate using an operating band having a first frequency range (FR1), which may span from 410 MHz to 7.125 GHz, and/or may communicate using an operating band having a second frequency range (FR2), which may span from 24.25 GHz to 52.6 GHz. The frequencies between FR1 and FR2 are sometimes referred to as mid-band frequencies. Although a portion of FR1 is greater than 6 GHz, FR1 is often referred to as a “sub-6 GHz” band. Similarly, FR2 is often referred to as a “millimeter wave” band despite being different from the extremely high frequency (EHF) band (30 GHz-300 GHz) which is identified by the International Telecommunications Union (ITU) as a “millimeter wave” band. Thus, unless specifically stated otherwise, it should be understood that the term “sub-6 GHz” or the like, if used herein, may broadly represent frequencies less than 6 GHz, frequencies within FRE and/or mid-band frequencies (e.g., greater than 7.125 GHz). Similarly, unless specifically stated otherwise, it should be understood that the term “millimeter wave” or the like, if used herein, may broadly represent frequencies within the EHF band, frequencies within FR2, and/or mid-band frequencies (e.g., less than 24.25 GHz). It is contemplated that the frequencies included in FR1 and FR2 may be modified, and techniques described herein are applicable to those modified frequency ranges.

In some aspects, the UE 120 may include a communication manager 140. As described in more detail elsewhere herein, the communication manager 140 may transmit an indication that the UE supports MIMO tone reservation; and receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication. Additionally, or alternatively, the communication manager 140 may perform one or more other operations described herein.

In some aspects, the base station 110 may include a communication manager 150. As described in more detail elsewhere herein, the communication manager 150 may receive an indication that a UE supports MIMO tone reservation; and transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication. Additionally, or alternatively, the communication manager 150 may perform one or more other operations described herein.

In some aspects, the UE 120 may include a communication manager 140. As described in more detail elsewhere herein, the communication manager 140 may transmit an indication that the UE supports MIMO tone reservation; and transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication. Additionally, or alternatively, the communication manager 140 may perform one or more other operations described herein.

In some aspects, the base station 110 may include a communication manager 150. As described in more detail elsewhere herein, the communication manager 150 may receive an indication that a UE supports MIMO tone reservation; and receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication. Additionally, or alternatively, the communication manager 150 may perform one or more other operations described herein.

As indicated above, FIG. 1 is provided as an example. Other examples may differ from what is described with regard to FIG. 1 .

FIG. 2 is a diagram illustrating an example 200 of a base station 110 in communication with a UE 120 in a wireless network 100, in accordance with the present disclosure. Base station 110 may be equipped with T antennas 234 a through 234 t, and UE 120 may be equipped with R antennas 252 a through 252 r, where in general T≥1 and R≥1.

At base station 110, a transmit processor 220 may receive data from a data source 212 for one or more UEs, select one or more modulation and coding schemes (MCS) for each UE based at least in part on channel quality indicators (CQIs) received from the UE, process (e.g., encode and modulate) the data for each UE based at least in part on the MCS(s) selected for the UE, and provide data symbols for all UEs. Transmit processor 220 may also process system information (e.g., for semi-static resource partitioning information (SRPI)) and control information (e.g., CQI requests, grants, and/or upper layer signaling) and provide overhead symbols and control symbols. Transmit processor 220 may also generate reference symbols for reference signals (e.g., a cell-specific reference signal (CRS) or a DMRS) and synchronization signals (e.g., a primary synchronization signal (PSS) or a secondary synchronization signal (SSS)). A transmit (TX) multiple-input multiple-output (MIMO) processor 230 may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, the overhead symbols, and/or the reference symbols, if applicable, and may provide T output symbol streams to T modulators (MODs) 232 a through 232 t. Each modulator 232 may process a respective output symbol stream (e.g., for OFDM) to obtain an output sample stream. Each modulator 232 may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. T downlink signals from modulators 232 a through 232 t may be transmitted via T antennas 234 a through 234 t, respectively.

At UE 120, antennas 252 a through 252 r may receive the downlink signals from base station 110 and/or other base stations and may provide received signals to demodulators (DEMODs) 254 a through 254 r, respectively. Each demodulator 254 may condition (e.g., filter, amplify, downconvert, and digitize) a received signal to obtain input samples. Each demodulator 254 may further process the input samples (e.g., for OFDM) to obtain received symbols. A MIMO detector 256 may obtain received symbols from all R demodulators 254 a through 254 r, perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor 258 may process (e.g., demodulate and decode) the detected symbols, provide decoded data for UE 120 to a data sink 260, and provide decoded control information and system information to a controller/processor 280. The term “controller/processor” may refer to one or more controllers, one or more processors, or a combination thereof. A channel processor may determine a reference signal received power (RSRP) parameter, a received signal strength indicator (RSSI) parameter, a reference signal received quality (RSRQ) parameter, and/or a CQI parameter, among other examples. In some aspects, one or more components of UE 120 may be included in a housing 284.

Network controller 130 may include communication unit 294, controller/processor 290, and memory 292. Network controller 130 may include, for example, one or more devices in a core network. Network controller 130 may communicate with base station 110 via communication unit 294.

Antennas (e.g., antennas 234 a through 234 t and/or antennas 252 a through 252 r) may include, or may be included within, one or more antenna panels, antenna groups, sets of antenna elements, and/or antenna arrays, among other examples. An antenna panel, an antenna group, a set of antenna elements, and/or an antenna array may include one or more antenna elements. An antenna panel, an antenna group, a set of antenna elements, and/or an antenna array may include a set of coplanar antenna elements and/or a set of non-coplanar antenna elements. An antenna panel, an antenna group, a set of antenna elements, and/or an antenna array may include antenna elements within a single housing and/or antenna elements within multiple housings. An antenna panel, an antenna group, a set of antenna elements, and/or an antenna array may include one or more antenna elements coupled to one or more transmission and/or reception components, such as one or more components of FIG. 2 .

On the uplink, at UE 120, a transmit processor 264 may receive and process data from a data source 262 and control information (e.g., for reports that include RSRP, RSSI, RSRQ, and/or CQI) from controller/processor 280. Transmit processor 264 may also generate reference symbols for one or more reference signals. The symbols from transmit processor 264 may be precoded by a TX MIMO processor 266 if applicable, further processed by modulators 254 a through 254 r (e.g., for DFT-s-OFDM or CP-OFDM), and transmitted to base station 110. In some aspects, a modulator and a demodulator (e.g., MOD/DEMOD 254) of the UE 120 may be included in a modem of the UE 120. In some aspects, the UE 120 includes a transceiver. The transceiver may include any combination of antenna(s) 252, modulators and/or demodulators 254, MIMO detector 256, receive processor 258, transmit processor 264, and/or TX MIMO processor 266. The transceiver may be used by a processor (e.g., controller/processor 280) and memory 282 to perform aspects of any of the methods described herein, for example, as described with reference to FIGS. 4-10 .

At base station 110, the uplink signals from UE 120 and other UEs may be received by antennas 234, processed by demodulators 232, detected by a MIMO detector 236 if applicable, and further processed by a receive processor 238 to obtain decoded data and control information sent by UE 120. Receive processor 238 may provide the decoded data to a data sink 239 and the decoded control information to controller/processor 240. Base station 110 may include communication unit 244 and communicate to network controller 130 via communication unit 244. Base station 110 may include a scheduler 246 to schedule UEs 120 for downlink and/or uplink communications. In some aspects, a modulator and a demodulator (e.g., MOD/DEMOD 232) of the base station 110 may be included in a modem of the base station 110. In some aspects, the base station 110 includes a transceiver. The transceiver may include any combination of antenna(s) 234, modulators and/or demodulators 232, MIMO detector 236, receive processor 238, transmit processor 220, and/or TX MIMO processor 230. The transceiver may be used by a processor (e.g., controller/processor 240) and memory 242 to perform aspects of any of the methods described herein, for example, as described with reference to FIGS. 4-10 .

Controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component(s) of FIG. 2 may perform one or more techniques associated with channel oriented tone reservation for multiple input multiple output communications, as described in more detail elsewhere herein. For example, controller/processor 240 of base station 110, controller/processor 280 of UE 120, and/or any other component(s) of FIG. 2 may perform or direct operations of, for example, process 700 of FIG. 7 , process 800 of FIG. 8 , process 900 of FIG. 9 , process 1000 of FIG. 10 , and/or other processes as described herein. Memories 242 and 282 may store data and program codes for base station 110 and UE 120, respectively. In some aspects, memory 242 and/or memory 282 may include a non-transitory computer-readable medium storing one or more instructions (e.g., code and/or program code) for wireless communication. For example, the one or more instructions, when executed (e.g., directly, or after compiling, converting, and/or interpreting) by one or more processors of the base station 110 and/or the UE 120, may cause the one or more processors, the UE 120, and/or the base station 110 to perform or direct operations of, for example, process 700 of FIG. 7 , process 800 of FIG. 8 , process 900 of FIG. 9 , process 1000 of FIG. 10 , and/or other processes as described herein. In some aspects, executing instructions may include running the instructions, converting the instructions, compiling the instructions, and/or interpreting the instructions, among other examples.

In some aspects, the UE includes means for transmitting an indication that the UE supports MIMO tone reservation; and/or means for receiving a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication. In some aspects, the UE includes means for transmitting an indication that the UE supports MIMO tone reservation; and/or means for transmitting a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication. The means for the UE to perform operations described herein may include, for example, one or more of communication manager 140, antenna 252, demodulator 254, MIMO detector 256, receive processor 258, transmit processor 264, TX MIMO processor 266, modulator 254, controller/processor 280, or memory 282.

In some aspects, the base station includes means for receiving an indication that a UE supports MIMO tone reservation; and/or means for transmitting a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication. In some aspects, the base station includes means for receiving an indication that a UE supports MIMO tone reservation; and/or means for receiving a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication. The means for the base station to perform operations described herein may include, for example, one or more of communication manager 150, transmit processor 220, TX MIMO processor 230, modulator 232, antenna 234, demodulator 232, MIMO detector 236, receive processor 238, controller/processor 240, memory 242, or scheduler 246.

While blocks in FIG. 2 are illustrated as distinct components, the functions described above with respect to the blocks may be implemented in a single hardware, software, or combination component or in various combinations of components. For example, the functions described with respect to the transmit processor 264, the receive processor 258, and/or the TX MIMO processor 266 may be performed by or under the control of controller/processor 280.

As indicated above, FIG. 2 is provided as an example. Other examples may differ from what is described with regard to FIG. 2 .

FIG. 3 is a diagram illustrating an example 300 of UE subcarrier tone reservation on one or more subcarriers, in accordance with the present disclosure. In some networks, a base station may transmit a downlink transmission on a physical downlink shared channel (PDSCH) with tone reservation on one or more subcarriers based at least in part on measurement(s) of uplink signals from a UE, a request from the UE, an indication of a capability of the UE, and/or an independent determination by the base station, among other examples (e.g., as described herein).

In some aspects, the UE may be configured to communicate with the base station with a configuration for tone reservation. For example, the configuration may be common for multiple communications (e.g., for a configured grant and/or semi-persistent scheduling resources), multiple UEs connected to the base station, a beam provided by the base station, a cell provided by the base station, and/or the like.

As shown by example 300, a PDSCH may include one or more reserved subcarriers (e.g., tones) on which data and/or pilots are not to be transmitted. In some aspects, the subcarriers may be empty (e.g., not having any information intended for transmission to the UE). Additionally, or alternatively, tone reservation may be applied to physical downlink control channel (PDCCH) symbols (e.g., symbols 0 and 1 in FIG. 3 ). In some aspects, a pilot may include or may be a reference signal. In some aspects, the base station may transmit a signal that is configured to improve a PAPR for a downlink transmission on the PDSCH by using tone reservation to forego transmission of data and/or pilots on the one or more reserved subcarriers. While example 300 provides an example of tone reservation applied to PDSCH and/or PDCCH, in some aspects (e.g., when a UE applies tone reservation to uplink communications transmitted to a base station), tone reservation may be applied to physical uplink shared channel (PUSCH) and/or physical uplink control channel (PUCCH) symbols.

Signaling for use of tone reservation may consume resources as overhead, which may decrease throughput and/or spectral efficiency. For example, to enable the UE to identify which subcarriers have tone reservation applied, the base station may indicate the frequency locations (e.g., using indices) of the subcarriers to the UE. These indications may consume communication, network, and power resources. Additionally, or alternatively, consumption of network resources for the indications may decrease throughput available for data (e.g., associated with the PDSCH). In a communication where tone reservation is not used, an increase in PAPR may occur, which may degrade communications between the base station and the UE, and may negatively affect an efficiency of power amplification at the base station. Based at least in part on degradation of the communications, the UE and/or the base station may consume power, communication, network, and computing resources to detect and/or correct communication errors associated with the degradation.

As indicated above, FIG. 3 is provided as an example. Other examples may differ from what is described with respect to FIG. 3 .

In some aspects described herein, a transmitting device (e.g., a base station or a UE, among other examples) may transmit an indication that tone reservation is to be applied to one or more subcarriers for a MIMO communication having multiple streams, and a receiving device (e.g., a UE or a base station, among other examples) may receive the indication. The indication may provide parameters for estimating TR subcarriers having tone reservation applied for the communication based at least in part on optimizing a peak-to-average-power ratio across the multiple streams of the MIMO communication.

The transmitting device may select the TR subcarriers based at least in part on an estimate of a channel response at the receiving device (e.g., may select TR subcarriers as the lowest capacity subcarriers of the communication as observed at the receiving device). The receiving device may estimate the TR subcarriers (e.g., attempt to identify the TR subcarriers) based at least in part on capacities of subcarriers of the communication, with the capacities determined using DMRSs and/or data symbols of the communication. Based at least in part on determining the capacities of the subcarriers, the receiving device may identify the TR subcarriers and decode the communication based at least in part on zeroing out the TR subcarriers or discarding the TR subcarriers.

FIG. 4 is a diagram illustrating an example 400 associated with channel oriented tone reservation for MIMO communications, in accordance with the present disclosure. As shown in FIG. 4 , a base station (e.g., base station 110) may communicate with a UE (e.g., UE 120). In some aspects, the base station and the UE may be part of a wireless network (e.g., wireless network 100). As shown in FIG. 4 , the base station may apply tone reservation for MIMO communications.

As shown by reference number 405, the base station may transmit, and the UE may receive, configuration information. In some aspects, the UE may receive the configuration information via one or more of radio resource control (RRC) signaling, medium access control (MAC) control elements (CEs) (MAC CEs), and/or downlink control information (DCI), among other examples. In some aspects, the configuration information may include an indication of one or more configuration parameters (e.g., already known to the UE) for selection by the UE, and/or explicit configuration information for the UE to use to configure the UE, among other examples.

In some aspects, the configuration information may indicate that the UE is to transmit an indication of UE support for MIMO tone reservation based at least in part on a downlink channel. In some aspects, the configuration information may indicate that the UE is to receive an indication that tone reservation is to be applied to one or more TR subcarriers for one or more MIMO communications. For example, the configuration information may indicate that the UE is to receive the indication via RRC signaling, MAC signaling, and/or DCI, among other examples. In some aspects, the indication may include an indication of a number of subcarriers to which tone reservation is to be applied, a fraction of subcarriers to which tone reservation is to be applied, a number of streams to which tone reservation is to be applied, and/or a threshold capacitance for subcarriers to which tone reservation is to be applied.

In some aspects, the configuration information may indicate that the UE is to transmit one or more uplink signals (e.g., sounding reference signals), using the one or more TR subcarriers (e.g., using subcarriers the same frequency ranges as the one or more TR subcarriers) on multiple streams associated with the MIMO communication, for measurement by the base station. In some aspects, the configuration information may indicate that the UE is to transmit an indication of a measurement of one or more signal-to-interference-plus-noise ratios (SINRs) based at least in part on reception of one or more downlink reference signals on the multiple streams associated with the MIMO communication. In some aspects, the configuration information may indicate that the UE is to determine a channel response of the one or more MIMO communications (e.g., based at least on part on DMRSs and/or data symbols of the one or more MIMO communications) and generate a set of estimated indices of the one or more TR subcarriers having tone reservation applied based at least in part on a capacity of the one or more TR subcarriers (e.g., a metric that accounts for energy, correlation between streams, interference between streams, and/or a likelihood of a receiving device decoding data carried by the TR subcarrier, among other examples). For example, the configuration information may indicate that the UE is to generate the set of estimated indices to include indices for one or more TR subcarriers having a lowest capacity of subcarriers of the one or more MIMO communications.

In some aspects, the configuration information may indicate that the UE is to decode the one or more MIMO communications based at least in part on discarding, rate matching, and/or zeroing out log likelihood ratios (LLRs) the one or more TR subcarriers.

As shown by reference number 410, the UE may configure the UE based at least in part on the configuration information. In some aspects, the UE may be configured to perform one or more operations described herein based at least in part on the configuration information.

As shown by reference number 415, the UE may transmit, and the base station may receive, an indication that the UE supports MIMO tone reservation applied based at least in part on a downlink channel. In some aspects, the UE may transmit the indication as part of an RRC configuration process. For example, the UE may transmit the indication in connection with a UE capability report during or after an RRC configuration process. In some aspects, the UE capability to receive the MIMO communications having the tone reservation applied may be based at least in part on a configuration of the UE, components of the UE, and/or availability of resources of the UE that may be used to determine subchannels to which tone reservation has been applied within a threshold amount of time.

As shown by reference number 420, the base station may transmit, and the UE may receive, one or more downlink signals, such as one or more downlink reference signals. In some aspects, the base station may transmit one or more channel state information reference signals (CSI-RSs) and/or one or more synchronization signal blocks (SSBs), among other examples, for the UE to measure via multiple streams associated with the MIMO communication. The UE may measure the one or more downlink signals to determine one or more SINRs associated with one or more channels via which the UE receives communications from the base station using the multiple streams.

As shown by reference number 425, the UE may transmit, and the base station may receive, a measurement report. In some aspects, the UE may transmit, and the base station may receive, a measurement of one or more SINRs that are based at least in part on reception of the one or more downlink signals received via the multiple streams. In some aspects, the base station may determine whether to use tone reservation for subsequent MIMO communications based at least in part on the measurement report. For example, the base station may determine to use tone reservation based at least in part on a relatively low SINR (e.g., less than or equal to a threshold) and/or may determine to not use tone reservation based at least in part on a relatively high SINR (e.g., greater than or equal to a threshold). In some aspects, the base station may determine an amount (e.g., a level or a degree) of tone reservation to apply based at least in part on the measurement report. For example, the base station may determine a number of subcarriers to which tone reservation is to be applied, a fraction of subcarriers to which tone reservation is to be applied, a number of streams on which tore reservation is to be applied, and/or a threshold power for subcarriers to which tone reservation is to be applied based at least in part on the one or more SINRs indicated in the measurement report.

As shown by reference number 430, the base station may transmit, and the UE may receive, an indication that tone reservation is to be applied to one or more TR subcarriers one or more MIMO communications.

In some aspects, the indication that tone reservation is to be applied may include an indication of a number of subcarriers to which tone reservation is to be applied, a fraction (e.g., percentage) of subcarriers to which tone reservation is to be applied, and/or a threshold power for subcarriers to which tone reservation is to be applied, among other examples. For example, the indication may include information that indicates that the N subcarriers with the lowest capacity and/or power (e.g., based on signal-to-noise ratio (SNR) measurements, SINR measurements, and/or RSSI measurements) are to have tone reservation applied, where N is a non-negative integer (e.g., a positive integer). As another example, the indication may include information that indicates a fraction or percentage (e.g., one fourth, one tenth, 5%, 10%, 20%, or the like) of subcarriers to which tone reservation is to be applied (e.g., subcarriers in the bottom fourth, tenth, 5%, 10%, 20%, or the like, in capacity and/or power). As yet another example, the indication may include information that indicates a threshold power (e.g., 0 dB, −5 dB, −10 dB, or the like), and that tone reservation is to be applied to subcarriers associated with uplink signals that fail to satisfy the threshold power.

In some aspects, the indication that tone reservation is to be applied may include information identifying a tone reservation optimization technique or formula. For example, based at least in part on the number of subcarriers, the fraction of subcarriers, and/or the threshold power for subcarriers to which tone reservation is to be applied, an optimization technique may be designed to identify subcarriers for tone reservation in a manner that optimizes PAPR with a constraint of a maximum power (e.g., transmit power) that is equal to the power used for the PDSCH and/or PUCCH subcarrier. In some aspects, the indication may include information that indicates that tone reservation optimization techniques are to be performed in iterations, are to be generated by applying machine learning, are to be generated using constrained or unconstrained optimization, or are to be generated by testing hypothesis iterations, among other examples. In some aspects, the indication may include information identifying a minimum tone reservation power constraint to be used (e.g., in a manner designed to improve UE detection).

In some aspects, the indication that tone reservation is to be applied may include information identifying a PAPR threshold to be achieved by tone reservation, and may include information indicating that various tone reservation and/or optimization techniques are to be used until the PAPR threshold is satisfied. For example, the indication may include information identifying the PAPR threshold and information indicating that the lowest capacity subcarriers are to be iteratively discarded until the PAPR threshold is reached (e.g., starting with discarding the lowest 1% of subcarriers and incrementing by +1% until the PAPR threshold is satisfied).

As shown by reference number 435, the UE may transmit, and the base station may receive, one or more uplink signals. In some aspects, the one or more uplink signals may be transmitted by the UE for measurement by the base station (e.g., for the base station to identify subcarriers to which tone reservation is to be applied). In some aspects, the one or more uplink signals include one or more sounding reference signals (SRSs).

As shown by reference number 440, the base station may apply tone reservation to one or more TR subcarriers of one or more MIMO communications (e.g., based at least in part on a capacity of the one or more uplink signals).

In some aspects, the base station may determine channel conditions (e.g., capacity measurements, one or more SINR values, and/or one or more PAPR values, among other examples) based at least in part on the one or more uplink signals and apply tone reservation based at least in part on the channel conditions. In some aspects, the base station may apply tone reservation to the one or more TR subcarriers based at least in part on the one or more TR subcarriers having a lowest capacity of subcarriers of the one or more uplink signals. In some aspects, the base station may apply tone reservation based at least in part on receiving the indication of the measurement of one or more SINRs (e.g., the measurement report described in connection with reference number 425) and/or based at least in part on transmission of one or more downlink reference signals (e.g., the downlink signals described in connection with reference number 420).

In some aspects, the base station may apply tone reservation to a number of subcarriers, a fraction (e.g., percentage) of subcarriers, and/or based at least in part on a threshold power for subcarriers, among other examples (e.g., as described herein). In some aspects, the base station may apply tone reservation using a tone reservation optimization technique (e.g., as described herein). In some aspects, the base station may apply tone reservation based at least in part on a PAPR threshold and/or various tone reservation and/or optimization techniques to be iteratively used until the PAPR threshold is satisfied (e.g., as described herein).

In some aspects, the base station may prepare a UE report indicating whether tone reservation is applied and indicating a number of subcarrier(s) (e.g., fraction or percentage) to which tone reservation is applied. In some aspects, the tone reservation frequency locations (e.g., subcarrier identifiers) and corresponding values may be identified to a mapper, along with data and/or pilots for transmission to the UE (e.g., using OFDM transmission protocol (e.g., inverse fast Fourier transform (IFFT))). The mapper may map the data and/or pilots to subcarriers of the channel, excluding subcarriers to which tone reservation is applied.

In some aspects, the base station may apply tone reservation to the one or more TR subcarriers based at least in part on channel capacity percentiles associated with the TR subcarriers on the multiple streams, capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, and/or channel covariance eigenvalues of the TR subcarriers on the multiple streams (e.g., subcarriers having smallest eigenvalues), among other examples. In some aspects, the base station may determine a number of the one or more TR subcarriers and/or a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is to be applied based at least in part on a PAPR threshold.

As shown by reference number 445, the UE may receive, and the base station may transmit, an indication of one or more parameters for estimating the TR subcarriers. In some aspects, the base station may transmit the indication of the one or more parameters via within DCI, such as a DCI that schedules the one or more MIMO communications.

In some aspects, the one or more parameters may include an explicit indication of the number of the TR subcarriers within the subsequent communication, an indication of a fraction of subcarriers of the communication that are TR subcarriers, or a threshold capacity for TR subcarriers. In some aspects, the one or more parameters may include channel capacity percentiles associated with the TR subcarriers on the multiple streams (e.g., being within the lower tenth percentile of capacity may indicate that a subcarrier is a TR subcarrier), capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues (e.g., an indication of a correlation between streams) of the TR subcarriers on the multiple streams.

As shown by reference number 450, the base station may transmit, and the UE may receive, one or more MIMO communications having the tone reservation applied to the one or more TR subcarriers. In some aspects, one or more TR subcarriers to which tone reservation is applied (e.g., by the base station) are based at least in part on the measurement of the one or more uplink signals on the subcarrier(s) (e.g., as described herein). As described above, the UE may receive an indication of the parameters for estimating the TR subcarriers along with (e.g., in a same set of allocated resources as) the one or more MIMO communications.

As shown by reference number 455, the UE may determine a channel response and/or estimate the one or more TR subcarriers on the multiple streams of the communication. In some aspects, the UE may estimate the TR subcarriers having tone reservation applied based at least in part on a capacity of the TR subcarriers. In some aspects, the UE may estimate the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel indicating that the TR subcarriers have a likelihood, that satisfies a threshold, of carrying data that will be decoded by the UE.

In some aspects, the UE may determine the channel response of the one or more MIMO communications, including one or more parameters of multiple streams of a downlink channel, to generate a set of estimated indices of the TR subcarriers and/or the TR subcarriers in the first set of the TR subcarriers. For example, the UE may generate the set of estimated indices based at least in part on a capacity of the one or more TR subcarriers of the one or more MIMO communications. In some aspects, the UE may generate the set of estimated indices based at least in part on the configuration information (e.g., described above in connection with reference number 405), and/or the indication that tone reservation is to be applied (e.g., described above in connection with reference number 430), among other examples. In some aspects, the UE may determine the channel response based at least in part on data symbols and/or DMRS symbols of the one or more MIMO communications (e.g., based at least in part on an estimation of the lowest capacity subcarriers using the data symbols and/or the DMRSs).

In some aspects, the UE may generate the set of estimated indices to indicate one or more TR subcarriers having lowest capacities of subcarriers used for the one or more MIMO communications. In some aspects, the set of estimated indices may include a number of indices based at least in part on information included in the indication that tone reservation is to be applied to the one or more TR subcarriers (e.g., described above in connection with reference number 430).

As shown by reference number 460, the UE may decode the one or more MIMO communications. In some aspects, the UE may decode the one or more MIMO communications based at least in part on the tone reservation being applied to the one or more TR subcarriers of the one or more MIMO communications. In some aspects, the UE may use information included in the indication that tone reservation is to be applied to the one or more TR subcarriers (e.g., described above in connection with reference number 430) to decode the one or more MIMO communications. In some aspects, the UE may decode the one or more MIMO communications based at least in part on discarding samplings received via the first set of the TR subcarriers and zeroing samplings received via the second set of the TR subcarriers. For example, the UE may estimate the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel and discard, rate match, or zero out signals received on the TR subcarrier. The UE may then decode the data subcarriers of the MIMO communication.

As indicated above, FIG. 4 is provided as an example. Other examples may differ from what is described with respect to FIG. 4 .

FIG. 5 is a diagram illustrating an example 500 associated with channel oriented tone reservation for MIMO communications, in accordance with the present disclosure. As shown in FIG. 5 , a base station (e.g., base station 110) may communicate with a UE (e.g., UE 120). In some aspects, the base station and the UE may be part of a wireless network (e.g., wireless network 100). As shown in FIG. 5 , the UE may apply tone reservation for MIMO communications.

As shown by reference number 505, the UE may receive, and the base station may transmit configuration information. In some aspects, the UE may receive the configuration information via one or more of RRC signaling, MAC CEs, and/or DCI, among other examples. In some aspects, the configuration information may include an indication of one or more configuration parameters (e.g., already known to the UE) for selection by the UE, and/or explicit configuration information for the UE to use to configure the UE, among other examples.

In some aspects, the configuration information may indicate that the UE is to receive an indication that tone reservation is to be applied to one or more TR subcarriers for one or more MIMO communications having multiple streams. For example, the configuration information may indicate that the UE is to receive the indication via RRC signaling, MAC signaling, and/or DCI, among other examples. In some aspects, the indication may include an indication of a number of subcarriers to which tone reservation is to be applied, a fraction of subcarriers to which tone reservation is to be applied, a number of streams to which tone reservation is to be applied, and/or a threshold capacitance for subcarriers to which tone reservation is to be applied. In some aspects, the configuration information may indicate that the UE is to transmit one or more uplink signals (e.g., sounding reference signals), using the one or more TR subcarriers on the multiple streams, for measurement by the base station. In some aspects, the configuration information may indicate that the UE is to determine a channel response of an uplink channel based at least in part on downlink signals received from the base station via the multiple streams. The configuration information may indicate that the UE is to apply tone reservation to the one or more TR subcarriers based at least in part on one or more parameters indicated by the base station.

As shown by reference number 510, the UE may configure the UE based at least in part on the configuration information. In some aspects, the UE may be configured to perform one or more operations described herein based at least in part on the configuration information.

As shown by reference number 515, the UE may transmit, and the base station may receive, an indication that the UE supports MIMO tone reservation applied based at least in part on an uplink channel. In some aspects, the UE may transmit the indication as part of an RRC configuration process. For example, the UE may transmit the indication in connection with a UE capability report during or after an RRC configuration process. In some aspects, the UE capability to transmit the MIMO communications having the tone reservation applied may be based at least in part on a configuration of the UE, components of the UE, and/or availability of resources of the UE that may be used to determine the one or more TR subcarriers, within a threshold amount of time, to which tone reservation is to be applied.

As shown by reference number 520, the UE may transmit, and the base station may receive, one or more uplink signals via the multiple streams associated with the MIMO communication. In some aspects, the one or more uplink signals may be transmitted by the UE for measurement by the base station (e.g., to enable the base station to determine whether tone reservation is to be applied to MIMO communications and/or to generate a measurement report for transmission to the base station, among other examples). In some aspects, the one or more uplink signals include one or more SRSs.

As shown by reference number 525, the base station may transmit, and the UE may receive, a measurement report. In some aspects, the base station may transmit a measurement of one or more SINRs that are based at least in part on reception of the one or more uplink signals. In some aspects, the UE may determine an amount (e.g., a level or a degree) of tone reservation to apply and/or may identify the one or more TR subcarriers based at least in part on the measurement report. For example, the UE may determine a number of subcarriers to which tone reservation is to be applied, a fraction of subcarriers to which tone reservation is to be applied, a number of streams on which tore reservation is to be applied, and/or a threshold power for subcarriers to which tone reservation is to be applied based at least in part on the one or more SINRs indicated in the measurement report.

As shown by reference number 530, the base station may transmit, and the UE may receive, an indication that tone reservation is to be applied to one or more TR subcarriers for one or more MIMO communications. In some aspects, the UE may receive the indication (e.g., MAC CE with a slot offset between a downlink allocation and corresponding data (KO) greater than or equal to 0) via RRC signaling, MAC signaling, and/or DCI, among other examples.

In some aspects, the indication that tone reservation is to be applied to one or more TR subcarriers for one or more MIMO communications may have one or more characteristics in common with the indication that tone reservation is to be applied to one or more TR subcarriers for one or more communications described in connection with reference number 430 of FIG. 4 .

As shown by reference number 535, the UE may receive, and the base station may transmit, one or more downlink signals via the multiple streams associated with the MIMO communication. In some aspects, the one or more downlink signals may be transmitted by the base station for measurement by the UE (e.g., to enable the UE to identify subcarriers to which tone reservation is to be applied). In some aspects, the one or more downlink signals may include one or more CSI-RSs, SSBs, or data channel signaling, among other examples. In some aspects, the UE may estimate a channel based at least in part on data symbols of the downlink signals, and/or based at least in part on DMRSs within a data channel and/or within a control channel to estimate a downlink channel including the multiple streams. For example, the UE may estimate the channel (e.g., the uplink channel) based at least in part on an assumption of reciprocity with the downlink channel.

As shown by reference number 540, the UE may receive, and the base station may transmit, an indication of one or more parameters that the base station uses for estimating the TR subcarriers. In some aspects, the base station may transmit the indication of the one or more parameters via within DCI, such as a DCI that schedules the one or more MIMO communications.

In some aspects, the one or more parameters may include an explicit indication of the number of the TR subcarriers within the subsequent communication, an indication of a fraction of subcarriers of the communication that are TR subcarriers, or a threshold capacity for TR subcarriers. In some aspects, the one or more parameters may include channel capacity percentiles associated with the TR subcarriers on the multiple streams (e.g., being within the lower tenth percentile of capacity may indicate that a subcarrier is a TR subcarrier), capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues (e.g., an indication of a correlation between streams) of the TR subcarriers on the multiple streams.

As shown by reference number 545, the UE may apply tone reservation to one or more TR subcarriers of one or more MIMO communications (e.g., based at least in part on a capacity of the one or more downlink signals). In some aspects, the UE may apply tone reservation to the one or more TR subcarriers for all of the multiple streams of the one or more MIMO communications, to different TR subcarriers for different streams of the multiple streams of the one or more MIMO communications, and/or for a subset of the multiple streams of the one or more MIMO communications, among other examples.

In some aspects, the UE may determine channel conditions (e.g., capacity measurements, one or more SINR values, and/or one or more PAPR values, among other examples) based at least in part on the one or more downlink signals and apply tone reservation based at least in part on the channel conditions. In some aspects, the UE may apply tone reservation to the one or more TR subcarriers based at least in part on the one or more TR subcarriers having a lowest capacity of subcarriers of the one or more downlink signals. In some aspects, the UE may apply tone reservation based at least in part on receiving the indication of the measurement of one or more SINRs (e.g., the measurement report described in connection with reference number 525) and/or based at least in part on transmission of one or more uplink reference signals (e.g., the downlink signals described in connection with reference number 535).

In some aspects, the UE may apply tone reservation to a number of subcarriers, a fraction (e.g., percentage) of subcarriers, and/or based at least in part on a threshold power for subcarriers, among other examples (e.g., as described herein). In some aspects, the UE may apply tone reservation using a tone reservation optimization technique (e.g., as described herein). In some aspects, the UE may apply tone reservation based at least in part on a PAPR threshold and/or various tone reservation and/or optimization techniques to be iteratively used until the PAPR threshold is satisfied (e.g., as described herein).

In some aspects, the UE may apply tone reservation based at least in part on an indication from the base station that indicates a number of subcarrier(s) (e.g., fraction or percentage) to which tone reservation is to be applied. In some aspects, the tone reservation frequency locations (e.g., subcarrier identifiers) and corresponding values may be identified to a mapper, along with data and/or pilots for transmission to the base station (e.g., using OFDM transmission protocol (e.g., IFFT)). The mapper may map the data and/or pilots to subcarriers of the channel, excluding subcarriers to which tone reservation is applied.

As shown by reference number 550, the UE may transmit, and the base station may receive, the one or more MIMO communications having the tone reservation applied to the one or more TR subcarriers. In some aspects, one or more TR subcarriers to which tone reservation is applied (e.g., by the UE) are based at least in part on the measurement of the one or more downlink signals on the one or more TR subcarriers (e.g., as described herein).

As shown by reference number 555, the base station may determine a channel response and/or estimate the one or more TR subcarriers on the multiple streams of the communication. In some aspects, the base station may estimate the TR subcarriers having tone reservation applied based at least in part on a capacity of the TR subcarriers. In some aspects, the base station may estimate the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel indicating that the TR subcarriers have a likelihood, that satisfies a threshold, of carrying data that will be decoded by the base station.

In some aspects, the base station may determine the channel response of the one or more MIMO communications, including one or more parameters of multiple streams of a downlink channel, to generate a set of estimated indices of the TR subcarriers and/or the TR subcarriers in the first set of the TR subcarriers. For example, the base station may generate the set of estimated indices based at least in part on a capacity of the one or more TR subcarriers of the one or more MIMO communications. In some aspects, the base station may generate the set of estimated indices based at least in part on the configuration information (e.g., described above in connection with reference number 505), and/or the indication that tone reservation is to be applied (e.g., described above in connection with reference number 530), among other examples. In some aspects, the base station may determine the channel response based at least in part on data symbols and/or DMRS symbols of the one or more MIMO communications (e.g., based at least in part on an estimation of the lowest capacity subcarriers using the data symbols and/or the DMRSs).

In some aspects, the base station may generate the set of estimated indices to indicate one or more TR subcarriers having lowest capacities of subcarriers used for the one or more MIMO communications. In some aspects, the set of estimated indices may include a number of indices based at least in part on information included in the indication that tone reservation is to be applied to the one or more TR subcarriers (e.g., described above in connection with reference number 530).

As shown by reference number 560, the base station may decode the one or more MIMO communications. In some aspects, the base station may decode the one or more MIMO communications based at least in part on the tone reservation being applied to the one or more TR subcarriers of the one more MIMO communications. In some aspects, the base station may use information included in the indication that tone reservation is to be applied to the one or more TR subcarriers (e.g., described above in connection with reference number 530) to decode the one or more MIMO communications. In some aspects, the base station may decode the one or more MIMO communications based at least in part on discarding samplings received via the first set of the TR subcarriers and zeroing samplings received via the second set of the TR subcarriers. For example, the base station may estimate the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel and discard, rate match, or zero out signals received on the TR subcarrier. The base station may then decode the data subcarriers of the MIMO communication.

As indicated above, FIG. 5 is provided as an example. Other examples may differ from what is described with respect to FIG. 5 .

FIG. 5 is a diagram illustrating an example 500 associated with channel oriented tone reservation for MIMO communications, in accordance with the present disclosure. As shown in FIG. 5 , a base station (e.g., base station 110) may communicate with a UE (e.g., UE 120). In some aspects, the base station and the UE may be part of a wireless network (e.g., wireless network 100). As shown in FIG. 5 , the UE may apply tone reservation for MIMO communications.

FIG. 6 is a diagram illustrating an example 600 associated with channel oriented tone reservation for MIMO communications, in accordance with the present disclosure. As shown in FIG. 6 , tone reservation may be applied to communications transmitted from a base station to a UE.

As shown in example 600, the base station may measure one or more UE SRSs (e.g., on multiple streams associated with the MIMO communication) to estimate an uplink channel. The base station may use the estimate of the uplink channel to estimate a downlink channel (e.g., using an assumption of reciprocity between the uplink channel and the downlink channel). In some aspects, the base station may use the estimate of the downlink channel to determine subcarriers and/or streams to which tone reservation is to be applied.

The base station may determine that tone reservation is to be applied to one or more subcarriers and/or streams for downlink transmissions to the UE (e.g., based at least in part on an SINR reported by the UE, the uplink channel estimate, other metrics associated with the uplink channel or the downlink channel, network traffic, and/or an amount of data buffered for transmission to the UE). When the base station determines that tone reservation is to be applied, the base station may then determine which subcarriers and/or streams are to be selected for tone reservation. In some aspects, selection of subcarriers may be based at least in part on a default number, such as the lowest 10% of subcarriers. In some aspects, selection of the default number may be based at least in part on the SINR measurements.

As shown by reference number 610, in some aspects, the base station may iteratively perform subcarrier selection techniques until a threshold PAPR value is reached. For example, the base station may use the UE downlink channel estimate, a default number of tones (e.g., subcarriers), and a default PAPR threshold to perform a selective mapping (SLM) technique, where alternative transmit sequence vectors (e.g., corresponding to the UE downlink channel) are generated from the same data source by multiplying the vectors by a random or pseudo-random phase. After multiplication, IFFT may be performed on the vectors to convert the corresponding signal from the frequency domain to the time domain, and PAPR values may be determined for each of the vectors. The PAPR values may be compared to one another in a manner designed to optimize tone reservation values by identifying a vector having tone reservations that result in a relatively low, or lowest, PAPR value with respect to other vectors. The base station may then determine whether the PAPR threshold is satisfied by the tone reservations indicated in the identified vector.

In some aspects, the subcarrier selection process may be performed up to k iterations, where k is a positive integer, and/or until a PAPR value that satisfies the threshold is reached. For example, if a default value (e.g., an initial value) for the number of subcarriers to which tone reservation is to be applied is 5%, and the subcarrier selection output fails to satisfy the PAPR threshold by applying tone reservation to the lowest 5% of subcarriers, the base station may increase the default value (e.g., by a fixed amount, variable amount, or fixed rate) and perform SLM again to determine if reserving the increased number of subcarriers (e.g., the lowest 6%) will satisfy the PAPR threshold. In some aspects, the PAPR threshold may be modified (e.g., lowered to decrease the number of subcarriers that would be reserved, or raised to increase the number of subcarriers that would be reserved) when iterating through the subcarrier selection process.

Once a tone reservation satisfying the PAPR threshold is identified, the base station may use the identified tone reservation and modulated data to remap the modulated data onto the multiple streams using the identified tone reservation scheme (e.g., application of tone reservation on the identified subchannels). For example, in a situation where the subcarrier selection process indicates that the lowest 6% of subcarriers (e.g., in terms of SINR) should be reserved to meet a given PAPR threshold, the modulated data may only be mapped to the top 94% subcarriers (e.g., based on received energy and/or power), leaving the bottom 6% reserved. After application of IFFT, the resulting downlink communication may be transmitted to the UE.

The UE may receive the downlink communication as RF signals on the multiple streams, and may use analog to digital conversion (ADC), using a configured number of bits, to provide digital output to a digital front end (DFE) of the UE. The UE may then apply a fast Fourier transform (FFT) algorithm to convert the received signals to a frequency domain and obtain the UE downlink communication.

The UE may decode a report of the tone reservation (e.g., included in DCI), which may indicate a number of subcarriers to which tone reservation was applied. For example, the report may indicate that tone reservation is to be applied to the lowest 6% of subcarriers.

The UE may use the downlink communication (e.g., data symbols and/or DMRSs) to estimate the capacity, eigenvalues (e.g., channel covariance eigenvalues), channel covariance determinants, channel covariance condition numbers of the subcarriers of the channel. After identifying the smallest (e.g., lowest) capacity subcarriers, and/or the smallest eigenvalues, the UE may generate a set of estimated indices associated with a hypothesis of the one or more subcarriers.

Additionally, or alternatively, the UE may use the downlink communication (e.g., data symbols and/or DMRSs) to estimate the energy (e.g., power) of the subcarriers of the channel (e.g., using SINR). After identifying the smallest (e.g., lowest) energy subcarriers (e.g., the bottom 6%), the UE may generate a set of estimated indices associated with a hypothesis of the one or more subcarriers.

As indicated above, FIG. 6 is provided as an example. Other examples may differ from what is described with respect to FIG. 6 .

FIG. 7 is a diagram illustrating an example process 700 performed, for example, by a UE, in accordance with the present disclosure. Example process 700 is an example where the UE (e.g., UE 120) performs operations associated with channel oriented tone reservation for MIMO communications.

As shown in FIG. 7 , in some aspects, process 700 may include transmitting an indication that the UE supports MIMO tone reservation (block 710). For example, the UE (e.g., using communication manager 140 and/or transmission component 1104, depicted in FIG. 11 ) may transmit an indication that the UE supports MIMO tone reservation, as described above.

As further shown in FIG. 7 , in some aspects, process 700 may include receiving a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication (block 720). For example, the UE (e.g., using communication manager 140 and/or reception component 1102, depicted in FIG. 11 ) may receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication, as described above.

Process 700 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In a first aspect, process 700 includes receiving an indication that the MIMO communication has tone reservation applied.

In a second aspect, process 700 includes receiving an indication of one or more of a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, a number of streams of the MIMO communication to which tone reservation is applied, a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is applied, or a fraction of subcarriers to which tone reservation is applied.

In a third aspect, process 700 includes receiving an indication that the TR subcarriers of the MIMO communication are selected based at least in part on one or more parameters of multiple streams of a downlink channel.

In a fourth aspect, the one or more parameters of the multiple streams of the downlink channel comprise one or more of channel capacity percentiles associated with the TR subcarriers on the multiple streams, capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues of the TR subcarriers on the multiple streams.

In a fifth aspect, process 700 includes transmitting one or more uplink signals for measurement by a base station to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of a downlink channel.

In a sixth aspect, process 700 includes determining a channel response of the MIMO communication, including one or more parameters of multiple streams of a downlink channel, estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel, and discarding, rate matching, or zeroing out signals received on the TR subcarriers.

In a seventh aspect, determining the channel response of the MIMO communication comprises determining the channel response based at least in part on one or more of demodulation reference signals or data symbols of the MIMO communication.

In an eighth aspect, estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel comprises estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel indicating that the TR subcarriers have a likelihood, that satisfies a threshold, of carrying data that will be decoded by the UE.

Although FIG. 7 shows example blocks of process 700, in some aspects, process 700 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. 7 . Additionally, or alternatively, two or more of the blocks of process 700 may be performed in parallel.

FIG. 8 is a diagram illustrating an example process 800 performed, for example, by a base station, in accordance with the present disclosure. Example process 800 is an example where the base station (e.g., base station 110) performs operations associated with channel oriented tone reservation for MIMO communications.

As shown in FIG. 8 , in some aspects, process 800 may include receiving an indication that a UE supports MIMO tone reservation (block 810). For example, the base station (e.g., using communication manager 150 and/or reception component 1202, depicted in FIG. 12 ) may receive an indication that a UE supports MIMO tone reservation, as described above.

As further shown in FIG. 8 , in some aspects, process 800 may include transmitting a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication (block 820). For example, the base station (e.g., using communication manager 150 and/or transmission component 1204, depicted in FIG. 12 ) may transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication, as described above.

Process 800 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In a first aspect, process 800 includes transmitting an indication that the MIMO communication has tone reservation applied.

In a second aspect, process 800 includes transmitting an indication of one or more of a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, a number of streams of the MIMO communication to which tone reservation is applied, a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is applied, or a fraction of subcarriers to which tone reservation is applied.

In a third aspect, process 800 includes transmitting an indication that the TR subcarriers of the MIMO communication are selected based at least in part on one or more parameters of multiple streams of a downlink channel.

In a fourth aspect, the one or more parameters of the multiple streams of the downlink channel comprise one or more of channel capacity percentiles associated with the TR subcarriers on the multiple streams, capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues of the TR subcarriers on the multiple streams.

In a fifth aspect, process 800 includes receiving one or more uplink signals for measurement by the base station to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of a downlink channel.

In a sixth aspect, process 800 includes determining a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is to be applied to satisfy a peak-to-average-power-ratio threshold.

In a seventh aspect, determining the number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is to be applied to satisfy the peak-to-average-power-ratio threshold comprises determining the number of subcarriers based at least in part on one or more of an iterative determination process based at least in part on projecting time-domain peaks on the TR subcarriers, or a model trained via machine learning based at least in part on prior determinations of numbers of subcarriers and feedback from one or more UEs.

In an eighth aspect, process 800 includes determining a tone reservation signal (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to apply to the TR subcarriers to satisfy a peak-to-average-power-ratio threshold.

In a ninth aspect, determining the tone reservation signal (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to apply to the TR subcarriers to satisfy the peak-to-average-power-ratio threshold comprises determining the tone reservation signal based at least in part on one or more of an iterative determination process based at least in part on projecting time-domain peaks on the TR subcarriers, or a model trained via machine learning based at least in part on prior determinations of tone reservation signals and feedback from one or more UEs.

In a tenth aspect, process 800 includes transmitting an indication of one or more metrics to be optimized via selection of the TR subcarriers, wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.

In an eleventh aspect, process 800 includes applying a precoder to tone reservation signals transmitted via the TR subcarriers before performing digital precoding of the MIMO communication on multiple streams, applying a precoder to tone reservation signals transmitted via the TR subcarriers after performing digital precoding of the MIMO communication on multiple streams, or applying a precoder to tone reservation signals transmitted via the TR subcarriers to improve self-interference of multiple streams and a peak-to-average-power-ratio of the MIMO communication.

Although FIG. 8 shows example blocks of process 800, in some aspects, process 800 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. 8 . Additionally, or alternatively, two or more of the blocks of process 800 may be performed in parallel.

FIG. 9 is a diagram illustrating an example process 900 performed, for example, by a UE, in accordance with the present disclosure. Example process 900 is an example where the UE (e.g., UE 120) performs operations associated with channel oriented tone reservation for multiple input multiple output communications.

As shown in FIG. 9 , in some aspects, process 900 may include transmitting an indication that the UE supports MIMO tone reservation (block 910). For example, the UE (e.g., using communication manager 140 and/or transmission component 1104, depicted in FIG. 11 ) may transmit an indication that the UE supports MIMO tone reservation, as described above.

As further shown in FIG. 9 , in some aspects, process 900 may include transmitting a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication (block 920). For example, the UE (e.g., using communication manager 140 and/or transmission component 1104, depicted in FIG. 11 ) may transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication, as described above.

Process 900 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In a first aspect, process 900 includes receiving an indication to apply tone reservation to the MIMO communication.

In a second aspect, process 900 includes receiving an indication of one or more of a number of subcarriers to which tone reservation is to be applied, a fraction of subcarriers to which tone reservation is to be applied, a threshold capacity for subcarriers to which tone reservation is to be applied, a number of streams of the MIMO communication to which tone reservation is to be applied, a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is to be applied, or a fraction of subcarriers to which tone reservation is to be applied.

In a third aspect, process 900 includes receiving an indication that the TR subcarriers of the MIMO communication are to be selected based at least in part on one or more parameters of multiple streams of a downlink channel.

In a fourth aspect, the one or more parameters of the multiple streams of the downlink channel comprise one or more of channel capacity percentiles associated with the TR subcarriers on the multiple streams, capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues of the TR subcarriers on the multiple streams.

In a fifth aspect, process 900 includes receiving one or more downlink signals for measurement by to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of an uplink channel.

In a sixth aspect, process 900 includes determining a tone reservation signal (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to apply to the TR subcarriers to satisfy a peak-to-average-power-ratio threshold.

In a seventh aspect, determining the tone reservation signal (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to apply to the TR subcarriers to satisfy the peak-to-average-power-ratio threshold comprises determining the tone reservation signal based at least in part on one or more of an iterative determination process based at least in part on projecting time-domain peaks on the TR subcarriers, or a model trained via machine learning based at least in part on prior determinations of tone reservation signals and feedback from one or more UEs.

In an eighth aspect, process 900 includes receiving an indication of one or more metrics to be optimized via selection of the TR subcarriers, wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.

In a ninth aspect, process 900 includes applying a precoder to tone reservation signals transmitted via the TR subcarriers before performing digital precoding of the MIMO communication on multiple streams, applying a precoder to tone reservation signals transmitted via the TR subcarriers after performing digital precoding of the MIMO communication on multiple streams, or applying a precoder to tone reservation signals transmitted via the TR subcarriers to improve self-interference of multiple streams and a peak-to-average-power-ratio of the MIMO communication.

Although FIG. 9 shows example blocks of process 900, in some aspects, process 900 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. 9 . Additionally, or alternatively, two or more of the blocks of process 900 may be performed in parallel.

FIG. 10 is a diagram illustrating an example process 1000 performed, for example, by a base station, in accordance with the present disclosure. Example process 1000 is an example where the base station (e.g., base station 110) performs operations associated with channel oriented tone reservation MIMO communications.

As shown in FIG. 10 , in some aspects, process 1000 may include receiving an indication that a UE supports MIMO tone reservation (block 1010). For example, the base station (e.g., using communication manager 150 and/or reception component 1202, depicted in FIG. 12 ) may receive an indication that a UE supports MIMO tone reservation, as described above.

As further shown in FIG. 10 , in some aspects, process 1000 may include receiving a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication (block 1020). For example, the base station (e.g., using communication manager 150 and/or reception component 12, depicted in FIG. 12 ) may receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication, as described above.

Process 1000 may include additional aspects, such as any single aspect or any combination of aspects described below and/or in connection with one or more other processes described elsewhere herein.

In a first aspect, process 1000 includes transmitting an indication that the MIMO communication has tone reservation applied.

In a second aspect, process 1000 includes transmitting an indication of one or more of a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, a number of streams of the MIMO communication to which tone reservation is applied, a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is applied, or a fraction of subcarriers to which tone reservation is applied.

In a third aspect, process 1000 includes transmitting an indication that the TR subcarriers of the MIMO communication are to be selected based at least in part on one or more parameters of multiple streams of a downlink channel.

In a fourth aspect, the one or more parameters of the multiple streams of the downlink channel comprise one or more of channel capacity percentiles associated with the TR subcarriers on the multiple streams, capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues of the TR subcarriers on the multiple streams.

In a fifth aspect, process 1000 includes transmitting one or more downlink signals for measurement by the UE to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of an uplink channel.

In a sixth aspect, process 1000 includes transmitting an indication of one or more metrics to be optimized via selection of the TR subcarriers, wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.

In a seventh aspect, process 1000 includes determining a channel response of the MIMO communication, including one or more parameters of multiple streams of an uplink channel, estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the uplink channel, and discarding, rate matching, or zeroing out signals received on the TR subcarriers.

In an eighth aspect, determining the channel response of the MIMO communication comprises determining the channel response based at least in part on one or more of demodulation reference signals or data symbols of the MIMO communication.

In a ninth aspect, estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel comprises estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel indicating that the TR subcarriers have a likelihood, that satisfies a threshold, of carrying data that will be decoded by the UE.

Although FIG. 10 shows example blocks of process 1000, in some aspects, process 1000 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted in FIG. 10 . Additionally, or alternatively, two or more of the blocks of process 1000 may be performed in parallel.

FIG. 11 is a block diagram of an example apparatus 1100 for wireless communication. The apparatus 1100 may be a UE, or a UE may include the apparatus 1100. In some aspects, the apparatus 1100 includes a reception component 1102 and a transmission component 1104, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus 1100 may communicate with another apparatus 1106 (such as a UE, a base station, or another wireless communication device) using the reception component 1102 and the transmission component 1104. As further shown, the apparatus 1100 may include a communication manager (e.g., the communication manager 140). The communication manager 140 may include a determination component and/or a mapping component, among other examples.

In some aspects, the apparatus 1100 may be configured to perform one or more operations described herein in connection with FIGS. 4-6 . Additionally, or alternatively, the apparatus 1100 may be configured to perform one or more processes described herein, such as process 700 of FIG. 7 , process 900 of FIG. 9 , or a combination thereof. In some aspects, the apparatus 1100 and/or one or more components shown in FIG. 11 may include one or more components of the UE described above in connection with FIG. 2 . Additionally, or alternatively, one or more components shown in FIG. 11 may be implemented within one or more components described above in connection with FIG. 2 . Additionally, or alternatively, one or more components of the set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by a controller or a processor to perform the functions or operations of the component.

The reception component 1102 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 1106. The reception component 1102 may provide received communications to one or more other components of the apparatus 1100. In some aspects, the reception component 1102 may perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, de-mapping, equalization, interference cancellation, or decoding, among other examples), and may provide the processed signals to the one or more other components of the apparatus 1106. In some aspects, the reception component 1102 may include one or more antennas, a demodulator, a MIMO detector, a receive processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with FIG. 2 .

The transmission component 1104 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 1106. In some aspects, one or more other components of the apparatus 1106 may generate communications and may provide the generated communications to the transmission component 1104 for transmission to the apparatus 1106. In some aspects, the transmission component 1104 may perform signal processing on the generated communications (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, among other examples), and may transmit the processed signals to the apparatus 1106. In some aspects, the transmission component 1104 may include one or more antennas, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the UE described above in connection with FIG. 2 . In some aspects, the transmission component 1104 may be co-located with the reception component 1102 in a transceiver.

The transmission component 1104 may transmit an indication that the UE supports MIMO tone reservation. The reception component 1102 may receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

The reception component 1102 may receive an indication that the MIMO communication has tone reservation applied.

The reception component 1102 may receive an indication of one or more of a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, a number of streams of the MIMO communication to which tone reservation is applied, a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is applied, or a fraction of subcarriers to which tone reservation is applied.

The reception component 1102 may receive an indication that the TR subcarriers of the MIMO communication are selected based at least in part on one or more parameters of multiple streams of a downlink channel.

The transmission component 1104 may transmit one or more of uplink signals for measurement by a base station to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of a downlink channel.

The communication manager 1108 may determine a channel response of the MIMO communication, including one or more parameters of multiple streams of a downlink channel.

The communication manager 1108 may estimate the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel.

The communication manager 1108 may discard, rate match, or zero out signals received on the TR subcarriers.

The transmission component 1104 may transmit an indication that the UE supports MIMO tone reservation. The transmission component 1104 may transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

The reception component 1102 may receive an indication to apply tone reservation to the MIMO communication.

The reception component 1102 may receive an indication of one or more of a number of subcarriers to which tone reservation is to be applied, a fraction of subcarriers to which tone reservation is to be applied, a threshold capacity for subcarriers to which tone reservation is to be applied, a number of streams of the MIMO communication to which tone reservation is to be applied, a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is to be applied, or a fraction of subcarriers to which tone reservation is to be applied.

The reception component 1102 may receive an indication that the TR subcarriers of the MIMO communication are to be selected based at least in part on one or more parameters of multiple streams of a downlink channel.

The reception component 1102 may receive one or more of downlink signals for measurement by to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of an uplink channel.

The communication manager 1108 may determine a tone reservation signal (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to apply to the TR subcarriers to satisfy a peak-to-average-power-ratio threshold.

The reception component 1102 may receive an indication of one or more metrics to be optimized via selection of the TR subcarriers wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.

The communication manager 1108 may apply a precoder to tone reservation signals transmitted via the TR subcarriers before performing digital precoding of the MIMO communication on multiple streams.

The communication manager 1108 may apply a precoder to tone reservation signals transmitted via the TR subcarriers after performing digital precoding of the MIMO communication on multiple streams.

The communication manager 1108 may apply a precoder to tone reservation signals transmitted via the TR subcarriers to improve self-interference of multiple streams and a peak-to-average-power-ratio of the MIMO communication.

FIG. 12 is a block diagram of an example apparatus 1200 for wireless communication. The apparatus 1200 may be a base station, or a base station may include the apparatus 1200. In some aspects, the apparatus 1200 includes a reception component 1202 and a transmission component 1204, which may be in communication with one another (for example, via one or more buses and/or one or more other components). As shown, the apparatus 1200 may communicate with another apparatus 1206 (such as a UE, a base station, or another wireless communication device) using the reception component 1202 and the transmission component 1204. As further shown, the apparatus 1200 may include the communication manager 150. The communication manager 150 may include a communication manager 1208 (e.g., communication manager 140).

In some aspects, the apparatus 1200 may be configured to perform one or more operations described herein in connection with FIGS. 4-6 . Additionally, or alternatively, the apparatus 1200 may be configured to perform one or more processes described herein, such as process 800 of FIG. 8 , process 1000 of FIG. 10 , or a combination thereof. In some aspects, the apparatus 1200 and/or one or more components shown in FIG. 12 may include one or more components of the base station described above in connection with FIG. 2 . Additionally, or alternatively, one or more components shown in FIG. 12 may be implemented within one or more components described above in connection with FIG. 2 . Additionally, or alternatively, one or more components of the set of components may be implemented at least in part as software stored in a memory. For example, a component (or a portion of a component) may be implemented as instructions or code stored in a non-transitory computer-readable medium and executable by a controller or a processor to perform the functions or operations of the component.

The reception component 1202 may receive communications, such as reference signals, control information, data communications, or a combination thereof, from the apparatus 1206. The reception component 1202 may provide received communications to one or more other components of the apparatus 1200. In some aspects, the reception component 1202 may perform signal processing on the received communications (such as filtering, amplification, demodulation, analog-to-digital conversion, demultiplexing, deinterleaving, de-mapping, equalization, interference cancellation, or decoding, among other examples), and may provide the processed signals to the one or more other components of the apparatus 1206. In some aspects, the reception component 1202 may include one or more antennas, a demodulator, a MIMO detector, a receive processor, a controller/processor, a memory, or a combination thereof, of the base station described above in connection with FIG. 2 .

The transmission component 1204 may transmit communications, such as reference signals, control information, data communications, or a combination thereof, to the apparatus 1206. In some aspects, one or more other components of the apparatus 1206 may generate communications and may provide the generated communications to the transmission component 1204 for transmission to the apparatus 1206. In some aspects, the transmission component 1204 may perform signal processing on the generated communications (such as filtering, amplification, modulation, digital-to-analog conversion, multiplexing, interleaving, mapping, or encoding, among other examples), and may transmit the processed signals to the apparatus 1206. In some aspects, the transmission component 1204 may include one or more antennas, a modulator, a transmit MIMO processor, a transmit processor, a controller/processor, a memory, or a combination thereof, of the base station described above in connection with FIG. 2 . In some aspects, the transmission component 1204 may be co-located with the reception component 1202 in a transceiver.

The reception component 1202 may receive an indication that a UE supports MIMO tone reservation. The transmission component 1204 may transmit a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

The transmission component 1204 may transmit an indication that the MIMO communication has tone reservation applied.

The transmission component 1204 may transmit an indication of one or more of a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, a number of streams of the MIMO communication to which tone reservation is applied, a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is applied, or a fraction of subcarriers to which tone reservation is applied.

The transmission component 1204 may transmit an indication that the TR subcarriers of the MIMO communication are selected based at least in part on one or more parameters of multiple streams of a downlink channel.

The reception component 1202 may receive one or more of uplink signals for measurement by the base station to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of a downlink channel.

The communication manager 1208 may determine a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is to be applied to satisfy a peak-to-average-power-ratio threshold.

The communication manager 1208 may determine a tone reservation signal (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to apply to the TR subcarriers to satisfy a peak-to-average-power-ratio threshold.

The transmission component 1204 may transmit an indication of one or more metrics to be optimized via selection of the TR subcarriers wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.

The communication manager 1208 may apply a precoder to tone reservation signals transmitted via the TR subcarriers before performing digital precoding of the MIMO communication on multiple streams.

The communication manager 1208 may apply a precoder to tone reservation signals transmitted via the TR subcarriers after performing digital precoding of the MIMO communication on multiple streams.

The communication manager 1208 may apply a precoder to tone reservation signals transmitted via the TR subcarriers to improve self-interference of multiple streams and a peak-to-average-power-ratio of the MIMO communication.

The reception component 1202 may receive an indication that a UE supports MIMO tone reservation. The reception component 1202 may receive a MIMO communication having tone reservation applied to TR subcarriers of the MIMO communication.

The transmission component 1204 may transmit an indication that the MIMO communication has tone reservation applied.

The transmission component 1204 may transmit an indication of one or more of a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, a number of streams of the MIMO communication to which tone reservation is applied, a number of subcarriers (e.g., a number per stream, a number for each stream, or total across multiple streams, among other examples) to which tone reservation is applied, or a fraction of subcarriers to which tone reservation is applied.

The transmission component 1204 may transmit an indication that the TR subcarriers of the MIMO communication are to be selected based at least in part on one or more parameters of multiple streams of a downlink channel.

The transmission component 1204 may transmit one or more of downlink signals for measurement by the UE to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of an uplink channel.

The transmission component 1204 may transmit an indication of one or more metrics to be optimized via selection of the TR subcarriers wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.

The communication manager 1208 may determine a channel response of the MIMO communication, including one or more parameters of multiple streams of an uplink channel.

The communication manager 1208 may estimate the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the uplink channel.

The communication manager 1208 may discard, rate match, or zero out signals received on the TR subcarriers.

The number and arrangement of components shown in FIG. 12 are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown in FIG. 12 . Furthermore, two or more components shown in FIG. 12 may be implemented within a single component, or a single component shown in FIG. 12 may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown in FIG. 12 may perform one or more functions described as being performed by another set of components shown in FIG. 12 .

The number and arrangement of components shown in FIG. 11 are provided as an example. In practice, there may be additional components, fewer components, different components, or differently arranged components than those shown in FIG. 11 . Furthermore, two or more components shown in FIG. 11 may be implemented within a single component, or a single component shown in FIG. 11 may be implemented as multiple, distributed components. Additionally, or alternatively, a set of (one or more) components shown in FIG. 11 may perform one or more functions described as being performed by another set of components shown in FIG. 11 .

The following provides an overview of some Aspects of the present disclosure:

Aspect 1: A method of wireless communication performed by a user equipment (UE), comprising: transmitting an indication that the UE supports multiple input multiple output (MIMO) tone reservation; and receiving a MIMO communication having tone reservation applied to tone reservation (TR) subcarriers of the MIMO communication.

Aspect 2: The method of Aspect 1, further comprising: receiving an indication that the MIMO communication has tone reservation applied.

Aspect 3: The method of any of Aspects 1-2, further comprising receiving an indication of one or more of: a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, a number of streams of the MIMO communication to which tone reservation is applied, a number of subcarriers to which tone reservation is applied, or a fraction of subcarriers to which tone reservation is applied.

Aspect 4: The method of any of Aspects 1-3, further comprising: receiving an indication that the TR subcarriers of the MIMO communication are selected based at least in part on one or more parameters of multiple streams of a downlink channel.

Aspect 5: The method of Aspect 4, wherein the one or more parameters of the multiple streams of the downlink channel comprise one or more of: channel capacity percentiles associated with the TR subcarriers on the multiple streams, capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues of the TR subcarriers on the multiple streams.

Aspect 6: The method of any of Aspects 1-5, further comprising transmitting one or more of: uplink signals for measurement by a base station to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of a downlink channel.

Aspect 7: The method of any of Aspects 1-6, further comprising: determining a channel response of the MIMO communication, including one or more parameters of multiple streams of a downlink channel; estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel; and discarding, rate matching, or zeroing out signals received on the TR subcarriers.

Aspect 8: The method of Aspect 7, wherein determining the channel response of the MIMO communication comprises: determining the channel response based at least in part on one or more of demodulation reference signals or data symbols of the MIMO communication.

Aspect 9: The method of Aspect 8, wherein estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel comprises: estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel indicating that the TR subcarriers have a likelihood, that satisfies a threshold, of carrying data that will be decoded by the UE.

Aspect 10: A method of wireless communication performed by a base station, comprising: receiving an indication that a user equipment (UE) supports multiple input multiple output (MIMO) tone reservation; and transmitting a MIMO communication having tone reservation applied to tone reservation (TR) subcarriers of the MIMO communication.

Aspect 11: The method of Aspect 10, further comprising: transmitting an indication that the MIMO communication has tone reservation applied.

Aspect 12: The method of any of Aspects 10-11, further comprising transmitting an indication of one or more of: a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, a number of streams of the MIMO communication to which tone reservation is applied, a number of subcarriers to which tone reservation is applied, or a fraction of subcarriers to which tone reservation is applied.

Aspect 13: The method of any of Aspects 10-12, further comprising: transmitting an indication that the TR subcarriers of the MIMO communication are selected based at least in part on one or more parameters of multiple streams of a downlink channel.

Aspect 14: The method of Aspect 13, wherein the one or more parameters of the multiple streams of the downlink channel comprise one or more of: channel capacity percentiles associated with the TR subcarriers on the multiple streams, capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues of the TR subcarriers on the multiple streams.

Aspect 15: The method of Aspect 10, further comprising receiving one or more of: uplink signals for measurement by the base station to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of a downlink channel.

Aspect 16: The method of any of Aspects 10-15, further comprising: determining a number of subcarriers to which tone reservation is to be applied to satisfy a peak-to-average-power-ratio threshold.

Aspect 17: The method of Aspect 16, wherein determining the number of subcarriers to which tone reservation is to be applied to satisfy the peak-to-average-power-ratio threshold comprises: determining the number of subcarriers based at least in part on one or more of: an iterative determination process based at least in part on projecting time-domain peaks on the TR subcarriers, or a model trained via machine learning based at least in part on prior determinations of numbers of subcarriers and feedback from one or more UEs.

Aspect 18: The method of any of Aspects 10-17, further comprising: determining a tone reservation signal to apply to the TR subcarriers to satisfy a peak-to-average-power-ratio threshold.

Aspect 19: The method of Aspect 18, wherein determining the tone reservation signal to apply to the TR subcarriers to satisfy the peak-to-average-power-ratio threshold comprises: determining the tone reservation signal based at least in part on one or more of: an iterative determination process based at least in part on projecting time-domain peaks on the TR subcarriers, or a model trained via machine learning based at least in part on prior determinations of tone reservation signals and feedback from one or more UEs.

Aspect 20: The method of any of Aspects 10-19, further comprising: transmitting an indication of one or more metrics to be optimized via selection of the TR subcarriers, wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.

Aspect 21: The method of any of Aspects 10-20, further comprising: applying a precoder to tone reservation signals transmitted via the TR subcarriers before performing digital precoding of the MIMO communication on multiple streams; applying a precoder to tone reservation signals transmitted via the TR subcarriers after performing digital precoding of the MIMO communication on multiple streams; or applying a precoder to tone reservation signals transmitted via the TR subcarriers to improve self-interference of multiple streams and a peak-to-average-power-ratio of the MIMO communication.

Aspect 22: A method of wireless communication performed by a user equipment (UE), comprising: transmitting an indication that the UE supports multiple input multiple output (MIMO) tone reservation; and transmitting a MIMO communication having tone reservation applied to tone reservation (TR) subcarriers of the MIMO communication.

Aspect 23: The method of Aspect 22, further comprising: receiving an indication to apply tone reservation to the MIMO communication.

Aspect 24: The method of any of Aspects 22-23, further comprising receiving an indication of one or more of: a number of subcarriers to which tone reservation is to be applied, a fraction of subcarriers to which tone reservation is to be applied, a threshold capacity for subcarriers to which tone reservation is to be applied, a number of streams of the MIMO communication to which tone reservation is to be applied, a number of subcarriers to which tone reservation is to be applied, or a fraction of subcarriers to which tone reservation is to be applied.

Aspect 25: The method of any of Aspects 22-24, further comprising: receiving an indication that the TR subcarriers of the MIMO communication are to be selected based at least in part on one or more parameters of multiple streams of a downlink channel.

Aspect 26: The method of Aspect 25, wherein the one or more parameters of the multiple streams of the downlink channel comprise one or more of: channel capacity percentiles associated with the TR subcarriers on the multiple streams, capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues of the TR subcarriers on the multiple streams.

Aspect 27: The method of any of Aspects 22-26, further comprising receiving one or more of: downlink signals for measurement by to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of an uplink channel.

Aspect 28: The method of any of Aspects 22-27, further comprising: determining a tone reservation signal to apply to the TR subcarriers to satisfy a peak-to-average-power-ratio threshold.

Aspect 29: The method of Aspect 28, wherein determining the tone reservation signal to apply to the TR subcarriers to satisfy the peak-to-average-power-ratio threshold comprises: determining the tone reservation signal based at least in part on one or more of: an iterative determination process based at least in part on projecting time-domain peaks on the TR subcarriers, or a model trained via machine learning based at least in part on prior determinations of tone reservation signals and feedback from one or more UEs.

Aspect 30: The method of Aspect 29, further comprising: receiving an indication of one or more metrics to be optimized via selection of the TR subcarriers, wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.

Aspect 31: The method of any of Aspects 22-29, further comprising: applying a precoder to tone reservation signals transmitted via the TR subcarriers before performing digital precoding of the MIMO communication on multiple streams; applying a precoder to tone reservation signals transmitted via the TR subcarriers after performing digital precoding of the MIMO communication on multiple streams; or applying a precoder to tone reservation signals transmitted via the TR subcarriers to improve self-interference of multiple streams and a peak-to-average-power-ratio of the MIMO communication.

Aspect 32: A method of wireless communication performed by a base station, comprising: receiving an indication that a user equipment (UE) supports multiple input multiple output (MIMO) tone reservation; and receiving a MIMO communication having tone reservation applied to tone reservation (TR) subcarriers of the MIMO communication.

Aspect 33: The method of Aspect 32, further comprising: transmitting an indication that the MIMO communication has tone reservation applied.

Aspect 34: The method of any of Aspects 32-33, further comprising transmitting an indication of one or more of: a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, a number of streams of the MIMO communication to which tone reservation is applied, a number of subcarriers to which tone reservation is applied, or a fraction of subcarriers to which tone reservation is applied.

Aspect 35: The method of any of Aspects 32-34, further comprising: transmitting an indication that the TR subcarriers of the MIMO communication are to be selected based at least in part on one or more parameters of multiple streams of a downlink channel.

Aspect 36: The method of Aspect 35, wherein the one or more parameters of the multiple streams of the downlink channel comprise one or more of: channel capacity percentiles associated with the TR subcarriers on the multiple streams, capacities of the TR subcarriers on the multiple streams, capacity percentiles associated with the TR subcarriers on the multiple streams, energies of the TR subcarriers on the multiple streams, channel covariance determinants of the TR subcarriers on the multiple streams, channel covariance condition numbers of the TR subcarriers on the multiple streams, or channel covariance eigenvalues of the TR subcarriers on the multiple streams.

Aspect 37: The method of any of Aspects 32-36, further comprising transmitting one or more of: downlink signals for measurement by the UE to determine the TR subcarriers for applying the tone reservation, or a measurement report indicating a channel response of an uplink channel.

Aspect 38: The method of any of Aspects 32-37, further comprising: transmitting an indication of one or more metrics to be optimized via selection of the TR subcarriers, wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.

Aspect 39: The method of any of Aspects 32-38, further comprising: determining a channel response of the MIMO communication, including one or more parameters of multiple streams of an uplink channel; estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the uplink channel; and discarding, rate matching, or zeroing out signals received on the TR subcarriers.

Aspect 40: The method of Aspect 39, wherein determining the channel response of the MIMO communication comprises: determining the channel response based at least in part on one or more of demodulation reference signals or data symbols of the MIMO communication.

Aspect 41: The method of any of Aspects any of Aspects 39-40, wherein estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel comprises: estimating the TR subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel indicating that the TR subcarriers have a likelihood, that satisfies a threshold, of carrying data that will be decoded by the UE.

Aspect 42: An apparatus for wireless communication at a device, comprising a processor; memory coupled with the processor; and instructions stored in the memory and executable by the processor to cause the apparatus to perform the method of one or more of Aspects 1-41.

Aspect 43: A device for wireless communication, comprising a memory and one or more processors coupled to the memory, the one or more processors configured to perform the method of one or more of Aspects 1-41.

Aspect 44: An apparatus for wireless communication, comprising at least one means for performing the method of one or more of Aspects 1-41.

Aspect 45: A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to perform the method of one or more of Aspects 1-41.

Aspect 46: A non-transitory computer-readable medium storing a set of instructions for wireless communication, the set of instructions comprising one or more instructions that, when executed by one or more processors of a device, cause the device to perform the method of one or more of Aspects 1-41.

The foregoing disclosure provides illustration and description, but is not intended to be exhaustive or to limit the aspects to the precise forms disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.

As used herein, the term “component” is intended to be broadly construed as hardware and/or a combination of hardware and software. “Software” shall be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, and/or functions, among other examples, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. As used herein, a processor is implemented in hardware and/or a combination of hardware and software. It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods were described herein without reference to specific software code—it being understood that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein.

As used herein, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, or the like.

Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various aspects includes each dependent claim in combination with every other claim in the claim set. As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items and may be used interchangeably with “one or more.” Further, as used herein, the article “the” is intended to include one or more items referenced in connection with the article “the” and may be used interchangeably with “the one or more.” Furthermore, as used herein, the terms “set” and “group” are intended to include one or more items (e.g., related items, unrelated items, or a combination of related and unrelated items), and may be used interchangeably with “one or more.” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise. Also, as used herein, the term “or” is intended to be inclusive when used in a series and may be used interchangeably with “and/or,” unless explicitly stated otherwise (e.g., if used in combination with “either” or “only one of”). 

What is claimed is:
 1. A user equipment (UE) for wireless communication, comprising: one or more memories; and one or more processors, coupled to the one or more memories, configured to: transmit an indication that the UE supports multiple input multiple output (MIMO) tone reservation; receive a MIMO communication having tone reservation applied to tone reservation subcarriers of the MIMO communication; and estimate frequency locations of the tone reservation subcarriers having tone reservation applied based at least in part on receiving the MIMO communication.
 2. The UE of claim 1, wherein the one or more processors are further configured to: receive an indication that the MIMO communication has tone reservation applied.
 3. The UE of claim 1, wherein the one or more processors are further configured to receive an indication of one or more of: a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, or a number of streams of the MIMO communication to which tone reservation is applied.
 4. The UE of claim 1, wherein the one or more processors are further configured to: receive an indication that the tone reservation subcarriers of the MIMO communication are selected based at least in part on one or more parameters of multiple streams of a downlink channel.
 5. The UE of claim 4, wherein the one or more parameters of the multiple streams of the downlink channel comprise one or more of: channel capacity percentiles associated with the tone reservation subcarriers on the multiple streams, capacities of the tone reservation subcarriers on the multiple streams, energies of the tone reservation subcarriers on the multiple streams, channel covariance determinants of the tone reservation subcarriers on the multiple streams, channel covariance condition numbers of the tone reservation subcarriers on the multiple streams, or channel covariance eigenvalues of the tone reservation subcarriers on the multiple streams.
 6. The UE of claim 1, wherein the one or more processors are further configured to transmit one or more of: uplink signals for measurement by a network entity to determine the tone reservation subcarriers for applying the tone reservation, or a measurement report indicating a channel response of a downlink channel.
 7. The UE of claim 1, wherein the one or more processors are further configured to: determine a channel response of the MIMO communication, including one or more parameters of multiple streams of a downlink channel, wherein estimating the frequency locations of the tone reservation subcarriers having tone reservation applied is based at least in part on the one or more parameters of the multiple streams of the downlink channel; and discard, rate match, or zero out signals received on the tone reservation subcarriers.
 8. The UE of claim 7, wherein the one or more processors, to determine the channel response of the MIMO communication, are configured to: determine the channel response based at least in part on one or more of demodulation reference signals or data symbols of the MIMO communication.
 9. The UE of claim 7, wherein the one or more processors, to estimate the frequency locations of the tone reservation subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel, are configured to: estimate the frequency locations of the tone reservation subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel indicating that the tone reservation subcarriers have a likelihood, that satisfies a threshold, of carrying data that will be decoded by the UE.
 10. A user equipment (UE) for wireless communication, comprising: one or more memories; and one or more processors, coupled to the one or more memories, configured to: transmit an indication that the UE supports multiple input multiple output (MIMO) tone reservation; and transmit a MIMO communication having tone reservation applied to tone reservation subcarriers of the MIMO communication, wherein the tone reservation subcarriers are selected based at least in part on one or parameters of multiple streams of a downlink channel.
 11. The UE of claim 10, wherein the one or more processors are further configured to: receive an indication to apply tone reservation to the MIMO communication.
 12. The UE of claim 10, wherein the one or more processors are further configured to receive an indication of one or more of: a number of subcarriers to which tone reservation is to be applied, a fraction of subcarriers to which tone reservation is to be applied, a threshold capacity for subcarriers to which tone reservation is to be applied, or a number of streams of the MIMO communication to which tone reservation is to be applied.
 13. The UE of claim 10, wherein the one or more processors are further configured to: receive an indication that the tone reservation subcarriers of the MIMO communication are to be selected based at least in part on the one or more parameters of the multiple streams of the downlink channel.
 14. The UE of claim 13, wherein the one or more parameters of the multiple streams of the downlink channel comprise one or more of: channel capacity percentiles associated with the tone reservation subcarriers on the multiple streams, capacities of the tone reservation subcarriers on the multiple streams, capacity percentiles associated with the tone reservation subcarriers on the multiple streams, energies of the tone reservation subcarriers on the multiple streams, channel covariance determinants of the tone reservation subcarriers on the multiple streams, channel covariance condition numbers of the tone reservation subcarriers on the multiple streams, or channel covariance eigenvalues of the tone reservation subcarriers on the multiple streams.
 15. The UE of claim 10, wherein the one or more processors are further configured to receive one or more of: downlink signals for measurement by the UE to determine the tone reservation subcarriers for applying the tone reservation, or a measurement report indicating a channel response of an uplink channel.
 16. The UE of claim 10, wherein the one or more processors are further configured to: determine a tone reservation signal to apply to the tone reservation subcarriers to satisfy a peak-to-average-power-ratio threshold.
 17. The UE of claim 16, wherein the one or more processors, to determine the tone reservation signal to apply to the tone reservation subcarriers to satisfy the peak-to-average-power-ratio threshold, are configured to: determine the tone reservation signal based at least in part on one or more of: an iterative determination process based at least in part on projecting time-domain peaks on the tone reservation subcarriers, or a model trained via machine learning based at least in part on prior determinations of tone reservation signals and feedback from one or more UEs.
 18. The UE of claim 10, wherein the one or more processors are further configured to: receive an indication of one or more metrics to be optimized via selection of the tone reservation subcarriers, wherein the one or more metrics comprise a parameter for optimization of an average among multiple streams or for optimization of an extrema among the multiple streams.
 19. A method of wireless communication performed by a user equipment (UE), comprising: transmitting an indication that the UE supports multiple input multiple output (MIMO) tone reservation; receiving a MIMO communication having tone reservation applied to tone reservation subcarriers of the MIMO communication; and estimating frequency locations of the tone reservation subcarriers having tone reservation applied based at least in part on receiving the MIMO communication.
 20. The method of claim 19, further comprising: receiving an indication that the MIMO communication has tone reservation applied.
 21. The method of claim 19, further comprising receiving an indication of one or more of: a number of subcarriers to which tone reservation is applied, a fraction of subcarriers to which tone reservation is applied, a threshold capacity for subcarriers to which tone reservation is applied, or a number of streams of the MIMO communication to which tone reservation is applied.
 22. The method of claim 19, further comprising: receiving an indication that the tone reservation subcarriers of the MIMO communication are selected based at least in part on one or more parameters of multiple streams of a downlink channel.
 23. The method of claim 22, wherein the one or more parameters of the multiple streams of the downlink channel comprise one or more of: channel capacity percentiles associated with the tone reservation subcarriers on the multiple streams, capacities of the tone reservation subcarriers on the multiple streams, energies of the tone reservation subcarriers on the multiple streams, channel covariance determinants of the tone reservation subcarriers on the multiple streams, channel covariance condition numbers of the tone reservation subcarriers on the multiple streams, or channel covariance eigenvalues of the tone reservation subcarriers on the multiple streams.
 24. The method of claim 19, further comprising: determining a channel response of the MIMO communication, including one or more parameters of multiple streams of a downlink channel, wherein estimating the frequency locations of the tone reservation subcarriers having tone reservation applied is based at least in part on the one or more parameters of the multiple streams of the downlink channel; and discarding, rate matching, or zeroing out signals received on the tone reservation subcarriers.
 25. The method of claim 24, wherein estimating the frequency locations of the tone reservation subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel comprises: estimating the frequency locations of the tone reservation subcarriers having tone reservation applied based at least in part on the one or more parameters of the multiple streams of the downlink channel indicating that the tone reservation subcarriers have a likelihood, that satisfies a threshold, of carrying data that will be decoded by the UE.
 26. A method of wireless communication performed by a user equipment (UE), comprising: transmitting an indication that the UE supports multiple input multiple output (MIMO) tone reservation; and transmitting a MIMO communication having tone reservation applied to tone reservation subcarriers of the MIMO communication, wherein the tone reservation subcarriers are selected based at least in part on one or more parameters of multiple streams of a downlink channel.
 27. The method of claim 26, further comprising: receiving an indication to apply tone reservation to the MIMO communication.
 28. The method of claim 26, further comprising receiving an indication of one or more of: a number of subcarriers to which tone reservation is to be applied, a fraction of subcarriers to which tone reservation is to be applied, a threshold capacity for subcarriers to which tone reservation is to be applied, or a number of streams of the MIMO communication to which tone reservation is to be applied.
 29. The method of claim 26, further comprising: receiving an indication that the tone reservation subcarriers of the MIMO communication are to be selected based at least in part on the one or more parameters of the multiple streams of the downlink channel.
 30. The method of claim 29, wherein the one or more parameters of the multiple streams of the downlink channel comprise one or more of: channel capacity percentiles associated with the tone reservation subcarriers on the multiple streams, capacities of the tone reservation subcarriers on the multiple streams, capacity percentiles associated with the tone reservation subcarriers on the multiple streams, energies of the tone reservation subcarriers on the multiple streams, channel covariance determinants of the tone reservation subcarriers on the multiple streams, channel covariance condition numbers of the tone reservation subcarriers on the multiple streams, or channel covariance eigenvalues of the tone reservation subcarriers on the multiple streams. 